Chlamydomonas and Paramoecium are: (a) unicellular prokaryotic
(b) multicellular prokaryotic
(c) unicellular eukaryotic
(d) multicellular eukaryotic

(c) unicellular eukaryotic

Explanation:

Firstly, all prokaryotic cells are unicellular, they cannot be multicellular, so be cannot be correct.

Both Chlamydomonas and Paramoecium are single-celled organisms, so must be unicellular prokaryotic (a) or unicellular eukaryotic (c).

Chlamydomonas and Paramoecium are eukaryotic. They have membrane-bound organelles like a nucleus and food vacuoles. They are examples of protists.